Persistent contrast enhancement several months after laparoscopic cryoablation of the small renal mass may not indicate recurrent tumor.
OBJECTIVE
We evaluated the clinical implication of persistent contrast enhancement demonstrated several months after laparoscopic renal cryoablation of a small renal mass.


METHODS
Between September 2000 and May 2007, 30 patients underwent laparoscopic cryosurgery for an organ-confined renal tumor measuring <or=3.5 cm in diameter. A pure laparoscopic approach was used with third generation cryotechnology-17-gauge cryoprobes and argon-helium gas. The patients were followed by serial CT or MRI every 3 months after cryotherapy or until radiographic resolution of contrast enhancement at the site of ablation.


RESULTS
Of 30 patients (comprising 32 cases), by 3 months after cryosurgery, 27 (84.4%) treated renal masses demonstrated no contrast enhancement at the ablation site. However, 5 (15.6%) ablation sites showed enhancement at 3 months; three of those persisted by 6 months, but only one displayed enhancement by 9 months. The patient with persistent enhancement by 9 months underwent partial nephrectomy that demonstrated no recurrent cancer. All other enhancing ablation sites showed no enhancement by 10 months after cryotherapy without recurrence. No tumor, including those that demonstrated persistent enhancement after cryotherapy, showed enlargement at the ablation site.


CONCLUSIONS
This study demonstrates that persistent contrast enhancement at the cryoablation site is uncommon but may be detected by cross-sectional imaging up to 9 months after the procedure. The cause of persistent enhancement remains uncertain but may not be necessarily because of malignancy. These data suggest a benign etiology not necessitating further therapy and should be taken into account during post-treatment radiologic surveillance.
Stein
Alexandra J
AJ
Division of Urologic Surgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
Mayes
Janice M
JM
Mouraviev
Vladimir
V
Chen
Valerie H
VH
Nelson
Rendon C
RC
Polascik
Thomas J
TJ
D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003452:Cryosurgery / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011182:Postoperative Care; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D003287:Contrast Media